Manufacturers and users of semiconductor equipment rely upon standardized equipment specifications to ease system integration and factory design. An example of one such standard that is often relied upon is referred to as the BOLTS-M standard (SEMI E15, E63). This standard specifies a mechanical interface for mechanisms called loadports, among others, that are often coupled to equipment front-end modules (EFEM's) for handling semiconductor substrates. Loadports that are adapted to accommodate standard front opening unified pods (FOUP's) or cassettes can easily be made to meet the BOLTS-M standard as the robot in the EFEM is capable of reaching into the FOUP or cassette in the loadport to extract or replace wafers. Not so with wafers mounted on film frames.
Wafers on film frames tend to sag and pose a difficult handling proposition. Rather than using a spatulate end effector with a robot to pick up a film frame with a wafer or singlulated chips mounted thereon, a film frame handler extracts each film frame by sliding it from its cassette onto a platform. A specialized overhead end effector equipped system then picks up the film frame by applying vacuum against the upper surface of the film frame's frame and moves the film frame onto a top plate for processing, inspection, metrology, etc.
The footprint of mechanisms for reliably extracting and replacing film frames in a cassette is typically too large for incorporation into a BOLTS-M compatible loadport. Accordingly, film frame handlers tend to be specialized affairs that are typically single purpose, i.e. film frame only. Where provisions are made to handle wafers or substrates other than film frames, the flexibility and capability of such systems is necessarily limited to accommodate the film frame handling capability.
There is, therefore, a need for a modular loadport for handling substrates such as film frames or hoops that at least approximates the flexibility exhibited by substrate loadports that comply with industry standards such as the BOLTS-M standard.